1. Technical Field
The present invention relates to methods for producing a sintered compact.
2. Related Art
As a method for producing a compact when a metal product is produced by sintering a compact containing metal powder, metal injection molding (MIM), for example, by which metal powder and an organic binder are mixed and kneaded and injection molding is performed by using the kneaded mixture thus obtained has been known.
The organic binder is removed from the compact produced by MIM by a degreasing treatment (binder removal treatment), and the compact is then baked, whereby a sintered compact is obtained.
When the compact is baked, the brown body is placed inside a baking furnace and is heated under reduced pressure or in the presence of inert gas. As a result, a diffusion phenomenon occurs between particles of the metal powder. This causes gradual densification of the compact and the sintering thereof.
Incidentally, the brown body is put on a tray-shaped jig generally called a “setter”, and is placed inside the baking furnace while being put on the setter and is then baked. The setter is formed of ceramic materials such as mullite and has good heat resistance.
JP-A-2002-145672 discloses a ceramic setter formed of ceramic materials containing mullite.
However, when the above-described ceramic setter is  repeatedly used in a baking process, the setter deteriorates with time due to oxygen deficiency of the ceramic material. This undesirably causes defects such as a fracture or deformation.
Moreover, an insufficient increase of sintered density of the sintered compact as a result of oxygen deficiency of the ceramic material has also become a problem.